1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (C) 2006 Matthew Wilcox <matthew@wil.cx> |
4 | * Copyright (C) 2006-2009 Hewlett-Packard Development Company, L.P. |
5 | * Alex Chiang <achiang@hp.com> |
6 | */ |
7 | |
8 | #include <linux/kobject.h> |
9 | #include <linux/slab.h> |
10 | #include <linux/module.h> |
11 | #include <linux/pci.h> |
12 | #include <linux/err.h> |
13 | #include "pci.h" |
14 | |
15 | struct kset *pci_slots_kset; |
16 | EXPORT_SYMBOL_GPL(pci_slots_kset); |
17 | |
18 | static ssize_t pci_slot_attr_show(struct kobject *kobj, |
19 | struct attribute *attr, char *buf) |
20 | { |
21 | struct pci_slot *slot = to_pci_slot(kobj); |
22 | struct pci_slot_attribute *attribute = to_pci_slot_attr(attr); |
23 | return attribute->show ? attribute->show(slot, buf) : -EIO; |
24 | } |
25 | |
26 | static ssize_t pci_slot_attr_store(struct kobject *kobj, |
27 | struct attribute *attr, const char *buf, size_t len) |
28 | { |
29 | struct pci_slot *slot = to_pci_slot(kobj); |
30 | struct pci_slot_attribute *attribute = to_pci_slot_attr(attr); |
31 | return attribute->store ? attribute->store(slot, buf, len) : -EIO; |
32 | } |
33 | |
34 | static const struct sysfs_ops pci_slot_sysfs_ops = { |
35 | .show = pci_slot_attr_show, |
36 | .store = pci_slot_attr_store, |
37 | }; |
38 | |
39 | static ssize_t address_read_file(struct pci_slot *slot, char *buf) |
40 | { |
41 | if (slot->number == 0xff) |
42 | return sysfs_emit(buf, fmt: "%04x:%02x\n" , |
43 | pci_domain_nr(bus: slot->bus), |
44 | slot->bus->number); |
45 | |
46 | return sysfs_emit(buf, fmt: "%04x:%02x:%02x\n" , |
47 | pci_domain_nr(bus: slot->bus), |
48 | slot->bus->number, |
49 | slot->number); |
50 | } |
51 | |
52 | static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf) |
53 | { |
54 | return sysfs_emit(buf, fmt: "%s\n" , pci_speed_string(speed)); |
55 | } |
56 | |
57 | static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf) |
58 | { |
59 | return bus_speed_read(speed: slot->bus->max_bus_speed, buf); |
60 | } |
61 | |
62 | static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf) |
63 | { |
64 | return bus_speed_read(speed: slot->bus->cur_bus_speed, buf); |
65 | } |
66 | |
67 | static void pci_slot_release(struct kobject *kobj) |
68 | { |
69 | struct pci_dev *dev; |
70 | struct pci_slot *slot = to_pci_slot(kobj); |
71 | |
72 | dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n" , |
73 | slot->number, pci_slot_name(slot)); |
74 | |
75 | down_read(sem: &pci_bus_sem); |
76 | list_for_each_entry(dev, &slot->bus->devices, bus_list) |
77 | if (PCI_SLOT(dev->devfn) == slot->number) |
78 | dev->slot = NULL; |
79 | up_read(sem: &pci_bus_sem); |
80 | |
81 | list_del(entry: &slot->list); |
82 | |
83 | kfree(objp: slot); |
84 | } |
85 | |
86 | static struct pci_slot_attribute pci_slot_attr_address = |
87 | __ATTR(address, S_IRUGO, address_read_file, NULL); |
88 | static struct pci_slot_attribute pci_slot_attr_max_speed = |
89 | __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL); |
90 | static struct pci_slot_attribute pci_slot_attr_cur_speed = |
91 | __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL); |
92 | |
93 | static struct attribute *pci_slot_default_attrs[] = { |
94 | &pci_slot_attr_address.attr, |
95 | &pci_slot_attr_max_speed.attr, |
96 | &pci_slot_attr_cur_speed.attr, |
97 | NULL, |
98 | }; |
99 | ATTRIBUTE_GROUPS(pci_slot_default); |
100 | |
101 | static const struct kobj_type pci_slot_ktype = { |
102 | .sysfs_ops = &pci_slot_sysfs_ops, |
103 | .release = &pci_slot_release, |
104 | .default_groups = pci_slot_default_groups, |
105 | }; |
106 | |
107 | static char *make_slot_name(const char *name) |
108 | { |
109 | char *new_name; |
110 | int len, max, dup; |
111 | |
112 | new_name = kstrdup(s: name, GFP_KERNEL); |
113 | if (!new_name) |
114 | return NULL; |
115 | |
116 | /* |
117 | * Make sure we hit the realloc case the first time through the |
118 | * loop. 'len' will be strlen(name) + 3 at that point which is |
119 | * enough space for "name-X" and the trailing NUL. |
120 | */ |
121 | len = strlen(name) + 2; |
122 | max = 1; |
123 | dup = 1; |
124 | |
125 | for (;;) { |
126 | struct kobject *dup_slot; |
127 | dup_slot = kset_find_obj(pci_slots_kset, new_name); |
128 | if (!dup_slot) |
129 | break; |
130 | kobject_put(kobj: dup_slot); |
131 | if (dup == max) { |
132 | len++; |
133 | max *= 10; |
134 | kfree(objp: new_name); |
135 | new_name = kmalloc(size: len, GFP_KERNEL); |
136 | if (!new_name) |
137 | break; |
138 | } |
139 | sprintf(buf: new_name, fmt: "%s-%d" , name, dup++); |
140 | } |
141 | |
142 | return new_name; |
143 | } |
144 | |
145 | static int rename_slot(struct pci_slot *slot, const char *name) |
146 | { |
147 | int result = 0; |
148 | char *slot_name; |
149 | |
150 | if (strcmp(pci_slot_name(slot), name) == 0) |
151 | return result; |
152 | |
153 | slot_name = make_slot_name(name); |
154 | if (!slot_name) |
155 | return -ENOMEM; |
156 | |
157 | result = kobject_rename(&slot->kobj, new_name: slot_name); |
158 | kfree(objp: slot_name); |
159 | |
160 | return result; |
161 | } |
162 | |
163 | void pci_dev_assign_slot(struct pci_dev *dev) |
164 | { |
165 | struct pci_slot *slot; |
166 | |
167 | mutex_lock(&pci_slot_mutex); |
168 | list_for_each_entry(slot, &dev->bus->slots, list) |
169 | if (PCI_SLOT(dev->devfn) == slot->number) |
170 | dev->slot = slot; |
171 | mutex_unlock(lock: &pci_slot_mutex); |
172 | } |
173 | |
174 | static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) |
175 | { |
176 | struct pci_slot *slot; |
177 | |
178 | /* We already hold pci_slot_mutex */ |
179 | list_for_each_entry(slot, &parent->slots, list) |
180 | if (slot->number == slot_nr) { |
181 | kobject_get(kobj: &slot->kobj); |
182 | return slot; |
183 | } |
184 | |
185 | return NULL; |
186 | } |
187 | |
188 | /** |
189 | * pci_create_slot - create or increment refcount for physical PCI slot |
190 | * @parent: struct pci_bus of parent bridge |
191 | * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder |
192 | * @name: user visible string presented in /sys/bus/pci/slots/<name> |
193 | * @hotplug: set if caller is hotplug driver, NULL otherwise |
194 | * |
195 | * PCI slots have first class attributes such as address, speed, width, |
196 | * and a &struct pci_slot is used to manage them. This interface will |
197 | * either return a new &struct pci_slot to the caller, or if the pci_slot |
198 | * already exists, its refcount will be incremented. |
199 | * |
200 | * Slots are uniquely identified by a @pci_bus, @slot_nr tuple. |
201 | * |
202 | * There are known platforms with broken firmware that assign the same |
203 | * name to multiple slots. Workaround these broken platforms by renaming |
204 | * the slots on behalf of the caller. If firmware assigns name N to |
205 | * multiple slots: |
206 | * |
207 | * The first slot is assigned N |
208 | * The second slot is assigned N-1 |
209 | * The third slot is assigned N-2 |
210 | * etc. |
211 | * |
212 | * Placeholder slots: |
213 | * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify |
214 | * a slot. There is one notable exception - pSeries (rpaphp), where the |
215 | * @slot_nr cannot be determined until a device is actually inserted into |
216 | * the slot. In this scenario, the caller may pass -1 for @slot_nr. |
217 | * |
218 | * The following semantics are imposed when the caller passes @slot_nr == |
219 | * -1. First, we no longer check for an existing %struct pci_slot, as there |
220 | * may be many slots with @slot_nr of -1. The other change in semantics is |
221 | * user-visible, which is the 'address' parameter presented in sysfs will |
222 | * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the |
223 | * %struct pci_bus and bb is the bus number. In other words, the devfn of |
224 | * the 'placeholder' slot will not be displayed. |
225 | */ |
226 | struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, |
227 | const char *name, |
228 | struct hotplug_slot *hotplug) |
229 | { |
230 | struct pci_dev *dev; |
231 | struct pci_slot *slot; |
232 | int err = 0; |
233 | char *slot_name = NULL; |
234 | |
235 | mutex_lock(&pci_slot_mutex); |
236 | |
237 | if (slot_nr == -1) |
238 | goto placeholder; |
239 | |
240 | /* |
241 | * Hotplug drivers are allowed to rename an existing slot, |
242 | * but only if not already claimed. |
243 | */ |
244 | slot = get_slot(parent, slot_nr); |
245 | if (slot) { |
246 | if (hotplug) { |
247 | if ((err = slot->hotplug ? -EBUSY : 0) |
248 | || (err = rename_slot(slot, name))) { |
249 | kobject_put(kobj: &slot->kobj); |
250 | slot = NULL; |
251 | goto err; |
252 | } |
253 | } |
254 | goto out; |
255 | } |
256 | |
257 | placeholder: |
258 | slot = kzalloc(size: sizeof(*slot), GFP_KERNEL); |
259 | if (!slot) { |
260 | err = -ENOMEM; |
261 | goto err; |
262 | } |
263 | |
264 | slot->bus = parent; |
265 | slot->number = slot_nr; |
266 | |
267 | slot->kobj.kset = pci_slots_kset; |
268 | |
269 | slot_name = make_slot_name(name); |
270 | if (!slot_name) { |
271 | err = -ENOMEM; |
272 | kfree(objp: slot); |
273 | goto err; |
274 | } |
275 | |
276 | INIT_LIST_HEAD(list: &slot->list); |
277 | list_add(new: &slot->list, head: &parent->slots); |
278 | |
279 | err = kobject_init_and_add(kobj: &slot->kobj, ktype: &pci_slot_ktype, NULL, |
280 | fmt: "%s" , slot_name); |
281 | if (err) { |
282 | kobject_put(kobj: &slot->kobj); |
283 | goto err; |
284 | } |
285 | |
286 | down_read(sem: &pci_bus_sem); |
287 | list_for_each_entry(dev, &parent->devices, bus_list) |
288 | if (PCI_SLOT(dev->devfn) == slot_nr) |
289 | dev->slot = slot; |
290 | up_read(sem: &pci_bus_sem); |
291 | |
292 | dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n" , |
293 | slot_nr, pci_slot_name(slot)); |
294 | |
295 | out: |
296 | kfree(objp: slot_name); |
297 | mutex_unlock(lock: &pci_slot_mutex); |
298 | return slot; |
299 | err: |
300 | slot = ERR_PTR(error: err); |
301 | goto out; |
302 | } |
303 | EXPORT_SYMBOL_GPL(pci_create_slot); |
304 | |
305 | /** |
306 | * pci_destroy_slot - decrement refcount for physical PCI slot |
307 | * @slot: struct pci_slot to decrement |
308 | * |
309 | * %struct pci_slot is refcounted, so destroying them is really easy; we |
310 | * just call kobject_put on its kobj and let our release methods do the |
311 | * rest. |
312 | */ |
313 | void pci_destroy_slot(struct pci_slot *slot) |
314 | { |
315 | dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n" , |
316 | slot->number, kref_read(&slot->kobj.kref) - 1); |
317 | |
318 | mutex_lock(&pci_slot_mutex); |
319 | kobject_put(kobj: &slot->kobj); |
320 | mutex_unlock(lock: &pci_slot_mutex); |
321 | } |
322 | EXPORT_SYMBOL_GPL(pci_destroy_slot); |
323 | |
324 | #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE) |
325 | #include <linux/pci_hotplug.h> |
326 | /** |
327 | * pci_hp_create_module_link - create symbolic link to hotplug driver module |
328 | * @pci_slot: struct pci_slot |
329 | * |
330 | * Helper function for pci_hotplug_core.c to create symbolic link to |
331 | * the hotplug driver module. |
332 | */ |
333 | void pci_hp_create_module_link(struct pci_slot *pci_slot) |
334 | { |
335 | struct hotplug_slot *slot = pci_slot->hotplug; |
336 | struct kobject *kobj = NULL; |
337 | int ret; |
338 | |
339 | if (!slot || !slot->ops) |
340 | return; |
341 | kobj = kset_find_obj(module_kset, slot->mod_name); |
342 | if (!kobj) |
343 | return; |
344 | ret = sysfs_create_link(kobj: &pci_slot->kobj, target: kobj, name: "module" ); |
345 | if (ret) |
346 | dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n" , |
347 | ret); |
348 | kobject_put(kobj); |
349 | } |
350 | EXPORT_SYMBOL_GPL(pci_hp_create_module_link); |
351 | |
352 | /** |
353 | * pci_hp_remove_module_link - remove symbolic link to the hotplug driver |
354 | * module. |
355 | * @pci_slot: struct pci_slot |
356 | * |
357 | * Helper function for pci_hotplug_core.c to remove symbolic link to |
358 | * the hotplug driver module. |
359 | */ |
360 | void pci_hp_remove_module_link(struct pci_slot *pci_slot) |
361 | { |
362 | sysfs_remove_link(kobj: &pci_slot->kobj, name: "module" ); |
363 | } |
364 | EXPORT_SYMBOL_GPL(pci_hp_remove_module_link); |
365 | #endif |
366 | |
367 | static int pci_slot_init(void) |
368 | { |
369 | struct kset *pci_bus_kset; |
370 | |
371 | pci_bus_kset = bus_get_kset(bus: &pci_bus_type); |
372 | pci_slots_kset = kset_create_and_add(name: "slots" , NULL, |
373 | parent_kobj: &pci_bus_kset->kobj); |
374 | if (!pci_slots_kset) { |
375 | pr_err("PCI: Slot initialization failure\n" ); |
376 | return -ENOMEM; |
377 | } |
378 | return 0; |
379 | } |
380 | |
381 | subsys_initcall(pci_slot_init); |
382 | |